1. Field of the Invention
Example embodiments of the present invention relate to a system, for example, a portable communications apparatus, having a memory device accessible by a plurality of processors.
2. Description of the Related Art
Depending on the characteristics and functions of communications and/or operation systems of a portable communications system, a multi-processor system may be implemented, wherein each processor may have a particular task. For example, in a portable communications system, for example, a cellular phone, a baseband processor may process code data for use in communications and/or an application processor may process data, for example, pictures and/or moving images.
FIG. 1 illustrates a conventional portable communications system 100. Referring to FIG. 1, the conventional portable communications system 100 may include a baseband processor 110, which may process a signal received via an antenna 10 and an application processor 120, which may drive one or more multi-media devices. The baseband processor 110 may operate one or more communication modems, micro-processors, digital signal processors (DSPs), compressor/decompressors (CODECs), etc. The baseband processor 110 may use a NOR flash memory 112 and a small-capacity mobile DRAM (MDRAM) 114 to achieve high-speed data processing. The application processor 120 may include device drivers for driving one or more multi-media devices, for example, an input/output device (e.g., a keyboard, an LCD, a memory, an infrared, USB, a multi-media card (MMC), an SDIO card), an audio player, a camera, a video recorder etc. The application processor 120 may use a large-capacity MDRAM 122 and a NAND flash memory 124 to process large-capacity data.
In the conventional portable communications system 100 of FIG. 1, the baseband processor 110 exclusively uses the memory devices 112 and 114 and the application processor 120 exclusively uses the memory devices 122 and 124. The above-described structure may increase power consumption by the portable communications system 100 and the manufacturing costs thereof, in part, because the baseband processor 110 and application processor 120 do not share a memory device.
FIG. 2 describes a conventional portable communications apparatus that may have a memory that is used exclusively and/or shared by a plurality of processors. Referring to FIG. 2, the portable communications apparatus, which is indicated by reference numeral 50 herein, may include a plurality of processors 70 and 80 and a single memory device 30, which may have a single memory array 35.
The memory device 30 may be used to store data and/or instructions that may be executed by the processors 70 and 80. The memory array 35 may include parts 31, 32, and 33. The part 33 is used exclusively by the processor 70, so only the processor 70 can access the part 33. Similarly, the part 31 is used exclusively by the processor 80, so only the processor 80 can access the part 31. The part 32 allocated in the memory array 35 may be accessed by both the processors 70 and 80. For example, while one of the processors 70 and 80 reads out contents recorded in the part 32, the other can write data to the part 32.
In the portable communications apparatus 50, data processed by the processor 70 must be stored in the part 33 or 32 of the memory array 35, and data processed by the processor 80 must be stored in the part 31 or 32 of the memory array 35. If data to be processed by the processor 70 is stored in the part 31 of the memory array 35, the processor 70 cannot be used until the data stored in the part 31 is moved to the part 32 by processor 80. On the other hand, if data to be processed by the processor 80 is stored in the part 33 of the memory array 35, the processor 80 cannot be used until the data stored in the part 33 is moved to the part 32 by processor 70.
In other words, the processor 70 and/or the processor 80 are burdened with having to move data to be processed to the part 32, which is shared by the processors 70 and 80. The additional data moving operation may degrade the performance of the conventional portable communications apparatus 50 and/or increase the power consumption thereof.